1. Field of the Invention
The invention relates to a device for removing heavy contaminants from an apparatus for treating a fibrous suspension, in particular from a hydrocyclone for separating heavy contaminants from a fibrous suspension.
2. Discussion of Background Information
In many cases the fibrous suspension designated for paper production must be cleaned of the refuse contained therein—so-called foreign particles. This applies in particular in the case of recovered paper preparation.
Hydrocyclones are able to concentrate and drain out heavy contaminants in fibrous suspensions by centrifugal force. They are generally used in the removal of metal parts, glass fragments and stones. The materials or parts removed from the suspension in this manner can be removed from the closed system by a junk trap being attached to the corresponding devices. It is known per se how an extraction device of this type works: in general it has two shut-off devices, e.g., a first and a second slider, between which a lock chamber is located. As long as the first slider, which produces the connection between the lock chamber and the system guiding the suspension, is opened, the lock chamber fills continuously with the refuse to be removed. In other cases it is possible to keep the first slider closed for a longer period and to open it only in a time cycle, so that part of the refuse concentrated in the system reaches the lock chamber in batches. The actual extraction is carried out by closing the first slider and opening the second slider, whereby the contents located in the lock chamber can be emptied. As a rule, the contents fall out of the lock chamber due to their weight; but they can also be suctioned off or rinsed out. Extraction devices of the type under consideration here are usually operated automatically, i.e., a clocked control takes place whereby the shut-off devices open and close automatically.